Radial turbine wheel structure

ABSTRACT

A radial turbine wheel structure comprises a wheel disc, a plurality of full blades and a plurality of splitting blades. The splitting blades are disposed equidistantly around the wheel disc and are alternately disposed with the full blades. Wherein each of inlet shrouds, outlet shrouds, inlet hubs and outlet hubs separately has an included angle to a meridian plane of the wheel disc, and the full blades are related to the splitting blades in length. Hence, the radial turbine wheel is applied to the gas turbine generator set to increase the electricity generation efficiency of the gas turbine generator.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a turbine wheel structure, and more particularly to a radial turbine wheel structure is applied to a gas turbine generator.

2. Description of the Prior Art

A gas turbine generator conforms to the demands of the high heat efficiency and the lower air pollution. In addition, the gas turbine generator has the market competitiveness advantage of less elements, lower vibration class, lower noise, faster starting, longer life, smaller volume and lighter weight than the diesel generator, and without cooling device.

Although general gas turbine has extremely high burning efficiency, the simple-cycle small gas turbine set has heat efficiency about 13% to 17%. For this reason, generally, there are three ways to improve the heat efficiency of the gas turbine:

1. To improve the design of the burner for controlling gas temperature distribution and use the DLN (dry low NOx) and the catalyst to restrain the amount of the NOx;

2. To use the ceramics material to bear higher temperature for increasing the inlet temperature of the gas turbine; and

3. To install the heat exchanger to increase the heat efficiency of the gas turbine.

A gas turbine wheel had been designed by Turbo Tech Company, but the static adiabatic efficiency parameter gives 82% only. It needs to be improved. The other prior art of gas turbine wheel of the U.S. Pat. Nos. 5,213,473, 5,639,217 and 5,730,582 are disclosed in order to reduce friction loss and fluid resistance force between the wheels and the air.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a radial turbine wheel structure that using CFD design software to model a set of radial turbine blade forms, and verifying flow field distribution, friction loss, fluid resistance force and structure strength by a 3D analysis software to conform the blade contour and the wheel structure strength to fit in with the operation environment so as to improve the heat efficiency of the radial turbine and increase the electricity generation efficiency of the gas turbine generator.

For achieving the objective stated above, the present invention provides a radial turbine wheel structure, comprising a wheel disc, a plurality of full blades and a plurality of splitting blades. The splitting blades are disposed equidistantly around the wheel disc and are alternately disposed with the full blades. Wherein each shroud inlet angle of the full blades is 9.5 to 10.5 degrees, each shroud outlet angle of the full blades is 59.5 to 60.5 degrees, each hub inlet angle of the full blades is 1 to 2 degrees and each hub outlet angle of the full blades is 36.9 to 37.9 degrees; the proportion between each shroud outlet radius of the splitting blades and each shroud outlet radius of the full blades is 0.72 to 0.74, the proportion between each hub outlet radius of the splitting blades and each shroud outlet radius of the full blades is 0.29 to 0.31, the proportion between each shroud outlet axial length of the splitting blades and each shroud outlet axial length of the full blades is 0.66 to 0.68 and the proportion between each hub outlet axial length of the splitting blades and each shroud outlet axial length of the full blades is 0.73 to 0.75. Hence, the radial turbine wheel provides higher electricity generation efficiency of the gas turbine generator.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. Other advantages and features of the invention will be apparent from the following description, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of this invention may be better understood by referring to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front view of a wheel structure of the present invention;

FIG. 2 is a side view of the wheel structure of the present invention;

FIG. 3 is a partial enlarged perspective view of the wheel structure of the present invention;

FIG. 4 is an angle definition view of the present invention;

FIG. 5 is a schematic view of the present invention is applied to a gas turbine power system; and

FIG. 6 is a schematic view of the present invention is applied to a gas turbine generator.

The drawings will be described further in connection with the following detailed description of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is made to FIG. 1 which is a front view of a wheel structure of the present invention. The present invention provides a radial turbine wheel 1 comprises a wheel disc 11, a plurality of full blades 12 and a plurality of splitting blades 13. The numbers of the full blades 12 and the splitting blades 13 are both eight, and the full blades 12 are equidistantly disposed around the wheel disc 11 and the splitting blades 13 are equidistantly disposed around wheel disc 11 and alternately disposed with the full blades 12.

Reference is made to FIG. 2 which is a side view of the wheel structure of the present invention. The blade outlets of the full blades 12 are truncated to form the splitting blades 13, so the structure of the splitting blades 13 is identical with the blade inlets of the full blades 12.

Reference is made to FIG. 3 which is a partial enlarged perspective view of the wheel structure of the present invention. The blade structure of the full blades 12 and the splitting blades 13 are curved structure and rule surfaces, and each of the outlet shrouds 121, 131, inlet shrouds 122, 132, outlet hubs 123, 133 and inlet hubs 124, 134 separately has a corresponding equivalent included angle to a meridian plane (r-z plane is constructed from a radial plane of the wheel disc and an axial plane of the wheel disc) of the wheel disc 11.

The amount of the blades of the radial turbine wheel 1 affects an export force of the turbine, that is the amount of the blades are larger and the export force is larger. However, the amount of the blades are larger, the areas between the outlet blades are smaller; so that is easy to block the airflow so as to affect the power efficiency and also damage the blades. Hence, the amount of the blades of the radial turbine wheel 1 are sixteen, and the splitting blades 13 are truncated so as to increase the areas between the outlet blades and maintain the export force from sixteen blades to produce sufficient power efficiency. The main cause of the export force is the structure of the blades includes angle distributions of the blades, sizes of the blades and thickness distributions of the blades; hence, the present invention provides a blade structure for producing the best export force.

References are made from FIG. 2 to FIG. 4. A shroud outlet angle β1 is an included angle between the outlet shroud 121 and a meridian plane of the wheel disc 11, a shroud inlet angle β2 is an included angle between the inlet shroud 122 and the meridian plane of the wheel disc 11, a hub outlet angle β3 is an included angle between the outlet hub 123 and the meridian plane of the wheel disc 11 and a hub inlet angle β4 is an included angle between the inlet hub 124 and the meridian plane of the wheel disc 11. Each of the angles is defined: the shroud outlet angle β1 and the shroud inlet angle β2 are separately the included angle between a blade shroud curve C1 that an outer edge of the full blade 12 is projected in the meridian plane and the outlet shroud 121, and the included angle between the blade shroud curve C1 and the inlet shroud 122; the hub outlet angle β3 and the hub inlet angle β4 are separately the included angle between a blade hub curve C2 that is the intersection of the meridian plane and the wheel disc 11, and the outlet hub 123, and the included angle between the blade hub curve C2 and the inlet hub 124. The full blade 12 is disposed on the wheel disc 11, a shroud outlet axial length L1 of the full blade 12 is equal to a distance between the inlet hub 124 of the full blade 12 and the outlet shroud 121 in axial direction (z-direction); a shroud outlet radius R1 of the full blade 12 is equal to a distance between the outlet shroud 121 and an axial line of the wheel disc 11. The splitting blades 13 are formed by truncating the full blades 12, and therefore the splitting blades 13 are characterized in the positions of truncated points. A shroud outlet axial length L2 of the splitting blade 13 is equal to a distance between the inlet hub 134 of the splitting blade 13 and the outlet shroud 131 in axial direction; a hub outlet axial length L3 of the splitting blade 13 is equal to a distance between the inlet hub 134 of the splitting blade 13 and the outlet hub 133 in axial direction. In addition, a shroud outlet radius R2 of the splitting blade 13 is equal to a distance between the outlet shroud 131 and the axial line of the wheel disc 11; a hub outlet radius R3 of the splitting blade 13 is equal to a distance between the outlet hub 133 and the axial line of the wheel disc 11.

The radial turbine wheel structure is characterized in that wherein each shroud outlet angle β1 of the full blades 12 is 59.5 to 60.5 degrees, each shroud inlet angle β2 of the full blades 12 is 9.5 to 10.5 degrees, each hub outlet angle β3 of the full blades 12 is 36.9 to 37.9 degrees and each hub inlet angle β4 of the full blades 12 is 1 to 2 degrees. The proportion between each shroud outlet radius R2 of the splitting blades 13 and each shroud outlet radius R1 of the full blades 12 is 0.72 to 0.74, the proportion between each hub outlet radius R3 of the splitting blades 13 and each shroud outlet radius R1 of the full blades 12 is 0.29 to 0.31. In addition, the proportion between each shroud outlet axial length L2 of the splitting blades 13 and each shroud outlet axial length L1 of the full blades 12 is 0.66 to 0.68 and the proportion between each hub outlet axial length L3 of the splitting blades 13 and each shroud outlet axial length L1 of the full blades 12 is 0.73 to 0.75. Hence, the characteristics stated above make the radial turbine wheel 1 with a high export force and a high output power. Besides, when the proportion between each shroud outlet radius R2 of the splitting blades 13 and each shroud outlet radius R1 of the full blades 12 is 0.730 to 0.732 and the proportion between each hub outlet radius R3 of the splitting blades 13 and each hub outlet radius R1 of the full blades 12 is 0.304 to 0.306, the radial turbine wheel 1 provides the maximum of export force and the best output efficiency. The Static Adiabatic Efficiency parameter of the present invention is 85% that is calculated and simulated by the representative software of STAR_CD and ANSYS. Comparing with the gas turbine wheel designed by Turbo Tech Company, the present invention is better with more than 3% of static adiabatic efficiency.

Reference is made to FIG. 5. The radial turbine wheel structure of the present invention can applied to a gas turbine system 2. Firstly, a centrifugal compressor 212 of a power system 21 is rotated to draw in the ambient air and transmit the ambient air to a pot-shaped combustor 213, and a fuel supply device 22 provides fuel to the pot-shaped combustor 213 via a fuel control valve 221 for burning. And next, the gas produced is transmitted to a centripetal turbine 211, and the centripetal turbine 211 exhausts the gas to produce power. The centrifugal compressor 212 and the centripetal turbine 211 are connected with a drive shaft 214 and the centripetal turbine 211 outputs the power by the drive shaft 214, and a lubricant supply device 23 provides lubricant to the drive shaft 214 for lubricating.

Reference is made to FIG. 6. The radial turbine wheel structure of the present invention can also applied to a gas turbine generator. The gas turbine system 2 is connected with a speed reducer 25 by the drive shaft 214, and the speed reducer 25 is connected with a generator 24 by a coupling 253. Firstly, a starter 251 of the speed reducer 25 starts gear reducers 252 for rotating the centrifugal compressor 212 to draw in the ambient air and transmit the ambient air to the pot-shaped combustor 213. And next, the fuel supply device 22 provides fuel to the pot-shaped combustor 213 via the fuel control valve 221 for burning. The gas produced is exhausted by the centripetal turbine 211 to produce the power to rotate the gear reducers 252 so as to rotate the coupling 253 to drive the generator 24 to generate the electricity. Due to the high rotation speed of the centripetal turbine 211, the gear reducers 252 are used to reduce the speed of the centripetal turbine 211 to protect the generator 24. In addition, the lubricant supply device 23 provides the lubricant either to the drive shaft 214 or to the gear reducers 252.

Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims. 

1. A radial turbine wheel structure, comprising: a wheel disc; a plurality of full blades equidistantly disposed around the wheel disc; and a plurality of splitting blades equidistantly disposed around the wheel disc and alternately disposed with the full blades; wherein each shroud inlet angle of the full blades is 9.5 to 10.5 degrees, each shroud outlet angle of the full blades is 59.5 to 60.5 degrees, each hub inlet angle of the full blades is 1 to 2 degrees and each hub outlet angle of the full blades is 36.9 to 37.9 degrees; the proportion between each shroud outlet radius of the splitting blades and each shroud outlet radius of the full blades is 0.72 to 0.74, the proportion between each hub outlet radius of the splitting blades and each shroud outlet radius of the full blades is 0.29 to 0.31, the proportion between each shroud outlet axial length of the splitting blades and each shroud outlet axial length of the full blades is 0.66 to 0.68 and the proportion between each hub outlet axial length of the splitting blades and each shroud outlet axial length of the full blades is 0.73 to 0.75.
 2. The radial turbine wheel structure as in claim 1, wherein the numbers of the full blades and the splitting blades are both eight.
 3. The radial turbine wheel structure as in claim 1, wherein the shroud outlet angle is an included angle between an outlet shroud and a meridian plane of the wheel disc, the shroud inlet angle is an included angle between an inlet shroud and the meridian plane of the wheel disc, the hub outlet angle is an included angle between an outlet hub and the meridian plane of the wheel disc and the hub inlet angle is an included angle between an inlet hub and the meridian plane of the wheel disc.
 4. The radial turbine wheel structure as in claim 1, wherein the best proportion between each shroud outlet radius of the splitting blades and each shroud outlet radius of the full blades is 0.730 to 0.732.
 5. The radial turbine wheel structure as in claim 1, wherein the best proportion between each hub outlet radius of the splitting blades and each hub outlet radius of the full blades is 0.304 to 0.306. 